Objective: The aim was to evaluate whether the Fat-to-Lean Mass (FyM) ratio is associated to glucose metabolic disorders (GMD). Design: Cross-sectional population based study. Methods: Eligible subjects were healthy men and non-pregnant women with new diagnosis of GMD that were allocated into following groups: 1) Normal Glucose Tolerance (NGT), 2) Diabetes, 3) impaired fasting glucose (IFG) + impaired glucose tolerance (IGT), 4) IGT, and 5) IFG. The FyM index [Total body fat (Kg)/total lean mass (Kg)], and the odds ratio (OR) between FyM index and GMD were estimated. Results: A total of 875 individuals with average age 41.62 ± 12.3 were enrolled; of them, 645 (73.1%) women and 230 (22.8%) men; 521 (59.5%), 71 (8.1%), 85 (9.7%), 53 (6.0%), and 145 (16.6%) individuals were allocated into groups with NGT, diabetes, IFG + IGT, IGT, and IFG, respectively. The FyM was significantly associated with prediabetes and diabetes in women (OR 4.2; 95%CI 3.0-11.1 and OR = 7.2; 95%CI 2.0-15.2) and men (OR = 2.6; 95%CI 1.1-6.7 and OR = 4.6; 95%CI 1.4-15.1). In the overall population, the OR between FyM index with IGT, IFG, and IFG + IGT was 8.4 (95%CI 2.6-17.4), 5.2 (95%CI 2.6-10.6), and 6.1 (95%CI 1.8-9.5). Conclusion: The FyM index was strongly associated with all categories of GMD.